Voice packet assembling/disassembling apparatus

ABSTRACT

A small and economical voice packet assembling/disassembling (PAD) apparatus, which comprises only one packet assembler/disassembler for a plurality of channels. The packet assembler receives coded voice data from a plurality of CODECs provided for each channel, and assembles voice packets by using the coded voice data. The packet disassembler disassembles voice packets to coded voice data and supplies them to a plurality of CODECs provided for each channel.

BACKGROUND OF THE INVENTION

The present invention relates to a voice packet assembling/disassemblingapparatus which assembles and disassembles voice packets in a voicepacket communications system.

A voice packet communications system and apparatus are disclosed in"Voice packet system", K. Saito et al, Electrical CommunicationLaboratories Technical Journal of NTT, Vol. 38, No. 3, pp. 231-237,1989.

FIG. 3 illustrates a schematic view of a voice packet communicationssystem. In FIG. 3, voice terminal 1, such as a telephone set, isconnected to a Private Branch Exchange (PBX) 2. The PBX 2 is connectedto a voice Packet Assembler/Disassembler (PAD) 4 through an Interface(I/F) 3 which multiplexes 30 PCM channels. Interface 3 conforms to TTCof Japan or JJ-20.10, JJ 20.11 and JJ 20.12.

Voice signals input from the voice terminal 1 reach the voice PAD 4 viaPBX 2 and I/F 3. In the voice PAD 4, input voice signals are coded toembedded ADPCM. The voice PAD 4 is connected to a packet multiplexer 6via I/F 5 conforming to CCITT Recommendation X.21. The packetmultiplexer 6 is connected to another packet multiplexer via high speeddigital switch 7.

FIG. 4 illustrates a prior interleave process forassembling/disassembling packets containing upper bits and lower bits,respectively. In FIG. 4, the coded embedded ADPCM voice data are dividedinto upper bits and lower bits for each sample. Voice data for more thanone sample are collected and assembled into respective packets for upperbits and for lower bits by the interleave process. Then the packets aremultiplexed in the voice PAD 4.

Although the above explanation is concerned with transmission, theprocess of reception is generally the same, as explained below. Thevoice PAD 4 disassembles the received packets to coded embedded ADPCMvoice data for each sample, decodes these data to voice signals, andsends them to the PBX 2.

FIG. 5 illustrates a prior voice packet assembling/disassemblingapparatus which assembles and disassembles a voice packet. In FIG. 5,I/F 3 is connected to a PBX interface 8, and the PBX interface 8 isconnected to each CODEC 9-1 to 9-30, and each CODEC 9-1 to 9 30 isconnected to corresponding PAD 10-1 to 10-0. And all PADs 10-1 to 10-30are connected to the packet multiplexing part 15 which contains amultiplexer 11 for multiplexing the voice signals, a CPU 13 forcontrolling all the blocks in the PAD 4, a data memory 12 and a linecontrol circuit 14 which sends or receives packets.

At the transmitting side, voice signals from I/F 3 input to the CODECs 9are provided for each channel via PBX interface 8. Each CODEC 9-1 to9-30 codes the voice signals and sends them to PAD 10-1 to 10-30provided for each channel. Each PAD 10 samples the coded signals anddiscriminates the upper bits from the lower bits. All upper bits arecollected to upper blocks and lower bits are collected to lower blocks.Voice packets are assembled from these blocks by adding a header and aresent to the multiplexer 11. The multiplexer 11 multiplexes the voicepackets received from each PAD 10 and stores them into the data memory12. CPU 13 reads the voice packets stored in the data memory 12 andprovides them to the line control circuit 14. The line control circuit14 sends the voice packets to I/F 5 in accordance with the layer 2protocol.

On the other hand, at the receiving side, voice packets received fromI/F 5 are input to the PAD 10 provided for each channel via multiplexingpart 15. Each PAD 10 disassembles the voice packets into packetscontaining upper blocks and other packets containing lower blocks. EachPAD 10 rearranges these packets to the coded voice data for each sampleand then transmits them to its corresponding CODEC 9. Each CODEC 9decodes the coded voice data into voice signals and sends them to I/F 3via the PBX interface 3.

But, in the prior voice packet assembling/disassembling apparatus, itwas necessary to provide PAD parts for each channel. In the result, theconfiguration of the PAD parts becomes very large and expensive.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a small andeconomical voice packet assembling/disassembling apparatus comprising apacket assembling means which receives coded voice data from a CODECprovided for each channel and assembles voice packets from the codedvoice data, and a packet disassembling means which disassembles voicepackets to the coded voice data and sends them to a CODEC provided foreach channel.

BRIEF DESCRIPTION OF THE DRAWINGS

The operation and advantages of the present invention will be more fullyunderstood from the detailed description below, which should be read inconjunction with the accompanying drawings in which:

FIG. 1 is a block diagram showing an embodiment of a voice packetassembling/disassembling apparatus of the present invention;

FIG. 2 shows an assembling and disassembling process in the voice packetassembling/disassembling apparatus of the present invention;

FIG. 3 is a block diagram of a voice packet communications system;

FIG. 4 shows a prior interleave process for assembling/disassemblingpackets containing upper bits and lower bits, respectively; and

FIG. 5, is a block diagram of a voice packet apparatus of the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

One embodiment of the present invention will hereinafter be describedwith reference to FIGS. 1 and 2. FIG. 1 illustrates one embodiment of avoice packet assembling/disassembling part of the present invention. Asillustrated in FIG. 1, CODEC 9 is connected to a packet assembling part16 and a packet disassembling part 17 which are features of the presentinvention. The packet assembling part 16 and the packet disassemblingpart 17 are both connected to a voice packet transmitting and receivingpart 18.

The packet assembling part 16 comprises a CODEC interface 19 connectedto CODECs 9 provided for each channel and a packet assembling block 20which assembles the coded voice data via CODEC interface 19 to the voicepackets. The packet disassembling part 17 comprises a CODEC interface 21connected to CODECs 9 provided for each channel and a packetdisassembling block 22 which disassembles voice packets received fromthe voice packet transmitting and receiving part 18 and supplies thecoded voice data to CODECs 9 provided for each channel.

The voice packet transmitting and receiving part 18 comprises a two portmemory 23, 24 which are connected to the packet assembling block 20 andthe packet disassembling block 22, respectively, and data memory 45, CPU46 and line control circuit 47 which are generally similar to the priorart.

Operation of this embodiment of the invention is explained below for thetransmitting side. When the voice signals are supplied from a PBX 2 (notshown in the figures), the voice signals are coded to embedded ADPCM ineach CODEC 9. The coded voice data are input to the packet assemblingblock 20 through CODEC interface 19. Packet assembling block 20assembles the packets and sends them to 2P memory 23.

FIG. 2 illustrates assembling and disassembling processes of the presentinvention. In FIG. 2, coded voice data of Ns samples are constructedfrom the output of the channels of CODECs 9. Packet assembling block 20assembles one voice packet 200 by rearranging the bit array of the codedvoice data 100 of Ns samples. More precisely, one block 201-MSB isassembled from the Most Significant Bits (MSB) extracted from the codedvoice data of Ns samples. In the same way, next block 201-MSB-1 isassembled from the MSB-1 bits extracted from the coded voice data of Nssamples. The same assembling processes are carried on by extracting thebits on the same position of the coded voice data of Ns samples. At lastblock 201-LSB is assembled only from the Last Significant Bits (LSB)extracted from the coded voice data of Ns samples. One voice packet 200is assembled by collecting each block 201-MSB, 201-MSB-1, . . . ,201-LSB and adding header 210 which contains coding rules and some otherinformation.

In the above description, MSB is the most influential bit and MSB-1 is asubsequent influential bit, and LSB is the least influential bit for thevoice quality.

In FIG. 1, the voice packets assembled in this manner are stored onceinto the data memory 45 via 2P memory 23, and then supplied to the linecontrol circuit 47 under control of CPU 46, and then supplied to apacket multiplexer 6 (not shown in the figure) via I/F 5 in accordancewith the layer 2 protocol. The packet multiplexer 6 multiplexes theinput packets and sends them to a high speed digital switch 7, not shownin the figure. When the packet multiplexer 6 is congested, the packetmultiplexer 6 abandons the lower block 201 in the voice packet 200, forexample 201-LSB, in order to abate the congestion, and sets informationin the header 210 indicating that the 201-LSB is abandoned.

Operation of this embodiment of the invention is explained below for thereceiving side. The signals go through the system in the oppositedirection compared to the transmitting side. Namely, the voice packet200 is input to the packet disassembling block 22 via 2P memory 24. Thepacket disassembling block 22 disassembles the voice packet 200, andrestores the coded voice data 100 corresponding Ns samples using thebits in the block 201 and the block abandonment information in theheader 210.

If the blocks corresponding to the lower bits are abandoned by acongested multiplexer 6 in order to abate congestion, the coded voicedata 100 of Ns samples constructed only MSB and MSB-1 bit are restoredfrom MSB block (201-MSB) and MSB-1 block (201-MSB-1) corresponding tothe upper bits, by using the header 210 which contains the abandonmentinformation of the lower block 201, for example 201-LSB. The restoredcoded voice data 100 of Ns samples input to CODECs 9 provided for eachchannel in order of 0, 1 . . . , Ns-1 via CODEC interface 21 and aredecoded to voice signals. The decoded voice signals input to PBX 2 viaPBX interface 8 and interface I/F 3.

In the prior art, PAD parts 10 are provided for each channel. But in thepresent invention, only one assembling block 20 and one packetdisassembling block 22 are provided in one PAD apparatus. Therefore,this invention provides a very small and economical voice PAD apparatus.

What is claimed is:
 1. A voice packet assembling/disassembling apparatusfor a voice communication system having a voice terminal of a pluralityof channels, the apparatus comprising:a plurality of CODECs whereininput voice signals received from the voice terminal are coded for eachchannel; a packet assembling means for receiving said coded voicesignals from the plurality of CODECs and for assembling said coded voicesignals into voice packets and for providing voice packets to a packetmultiplexer; a packet disassembling means for receiving input voicepackets through the packet multiplexer and for disassembling saidreceived input voice packets into coded voice signals; said plurality ofCODECs decoding said coded voice signals into voice signals for eachchannel and for providing said voice signals to the voice terminal; andwherein said packet assembling means collects a plurality of bits whichare located at the same bit position in a first number of samplesreceived from said CODECs for making a plurality of blocks, andassembles voice packets from said plurality of blocks by adding a headerblock.
 2. The voice packet assembling/disassembling apparatus of claim 1wherein said packet disassembling means disassembles voice packetsincluding a header block into a plurality of blocks which containdifferent bit position data respectively, and restores coded data of thefirst number of samples from said plurality of blocks corresponding toeach channel.
 3. A voice packet assembling/disassembling apparatus for avoice communication system having a voice terminal of a plurality ofchannels, the apparatus comprising:a plurality of CODECs wherein inputvoice signals received from the voice terminal are coded for eachchannel; a packet assembling means for receiving said coded voicesignals from the plurality of CODECs and for assembling said coded voicesignals into voice packets and for providing voice packets to a packetmultiplexer; a packet disassembling means for receiving input voicepackets through the packet multiplexer and for disassembling saidreceived input voice packets into coded voice signals; said plurality ofCODECs decoding said coded voice signals into voice signals for eachchannel and for providing said voice signals to the voice terminal; andwherein said packet disassembling means disassemblies voice packetsincluding a header block into a plurality of blocks which containdifferent bit position data respectively, and restores coded data of afirst number of samples from said plurality of blocks corresponding toeach channel.
 4. A voice packet assembling/disassembling apparatus for avoice communication system having a voice terminal of a plurality ofchannels, the apparatus comprising:a plurality of CODECs for receivingvoice data from the voice terminal and for coding said voice data; onepacket assembling/disassembling means having means for receiving saidcoded voice data from said plurality of CODECs and assembling said codedvoice data into voice packets and for providing voice packets to apacket multiplexer to be provided to a packet multiplexer and means forreceiving voice packets from the packet multiplexer and disassemblingsaid voice packets into coded voice data; said plurality of CODECs alsoreceiving coded voice data from said packet assembling/disassemblingmeans and decoding said data into voice data to be provided to the voiceterminal; and wherein said means for assembling coded voice data intovoice packets collects a plurality of bits which are located at the samebit position in a first number of samples received from said CODECs formaking a plurality of blocks, said voice packets being assembled fromsaid plurality of blocks and a header block.
 5. The voice packetassembling/disassembling apparatus of claim 4, wherein voice packetsinclude a header block and said means for disassembling into a pluralityof blocks, disassembles voice packets each block containing differentbit position data, and restores coded data of the first number ofsamples from said plurality of blocks corresponding to each channel. 6.A voice packet assembling/disassembling apparatus for a voicecommunication system having a voice terminal of a plurality of channels,the apparatus comprising:a plurality of CODECs for receiving voice datafrom the voice terminal and for coding said voice data; one packetassembling/disassembling means having means for receiving said codedvoice data from said plurality of CODECs and assembling said coded voicedata into voice packets and for providing voice packets to a packetmultiplexer to be provided to a packet multiplexer and means forreceiving voice packets from the packet multiplexer and disassemblingsaid voice packets into coded voice data; said plurality of CODECs alsoreceiving coded voice data from said packet assembling/disassemblingmeans and decoding said data into voice data to be provided to the voiceterminal; and wherein voice packets include a header block and saidmeans for disassembling into a plurality of blocks, disassembles voicepackets each block containing different bit position data, and restorescoded data of the first number of samples from said plurality of blockscorresponding to each channel.
 7. A voice packetassembling/disassembling apparatus for a voice communication systemhaving a voice terminal of a plurality of channels, the apparatuscomprising:a plurality of CODECs wherein input voice signals receivedfrom the voice terminal are coded for each channel; a single CODECinterface, connected to receive coded voice data from the plurality ofCODECs; a single packet assembling means for receiving said coded voicesignals from the CODEC interface and for assembling said coded voicesignals into voice packets to be provided to a packet multiplexer; asingle packet disassembling means for receiving input voice packetsthrough the packet multiplexer and for disassembling said received inputvoice packets into coded voice signals; a second single CODEC interfaceconnected to the single packet disassembling means for receiving codedvoice signals therefrom; and said plurality of CODECs decoding saidcoded voice signals received from the second CODEC interface into voicesignals for each channel to be provided to the voice terminal.
 8. Theapparatus of claim 7, wherein the packet assembling means includes meansfor collecting a plurality of bits which are located at the same bitposition from a first number of samples received through said CODECinterface;means, responsive to the means for collecting, for making aplurality of blocks from the collected plurality of bits; and means,responsive to the means for collecting and means for making, forassembling voice packets from said plurality of blocks by adding aheader block.
 9. The apparatus of claim 8, wherein said packetdisassembling means includes means for disassembling voice packets,including a header block, into a plurality of blocks, wherein each blockcontains different bit position data, andmeans for restoring coded dataof a first number of samples from said plurality of blocks,corresponding to each channel.
 10. The apparatus of claim 7, furthercomprising a two part memory for receiving assembled packets from thepacket assembling means and for providing assembled packets to thepacket disassembling means;and a line control means for providing andreceiving assembled packets to and from the packet multiplexer.
 11. Theapparatus of claim 10, wherein the packet assembling means includesmeans for collecting a plurality of bits which are located at the samebit position from a first number of samples received through said CODECinterface;means, responsive to the means for collecting, for making aplurality of blocks from the collected plurality of bits; and means,responsive to the means for collecting and means for making, forassembling voice packets from said plurality of blocks by adding aheader block.
 12. The apparatus of claim 11, wherein said packetdisassembling means includes means for disassembling voice packets,including a header block, into a plurality of blocks, wherein each blockcontains different bit position data, andmeans for restoring coded dataof a first number of samples form said plurality of blocks,corresponding to each channel.